Influence of Processing Parameters on Clamping Force During Injection Molding Process

Clamping force is needed during injection molding process to keep the injection mold closed. It is a crucial parameter that must be considered during the process of plastic part development, because high clamping forces can be achieved with stronger (and more expensive) injection molding machine. It is economically wise to use processing parameters that can allow manufacturing of parts with smaller machines. The clamping force is a variable strictly related to pressure present in the cavity of the injection mold. In this study two parameters that strongly influence injection pressure (plastic flow rate and volume-to-pressure switch-over point) were examined with numerical simulations performed in Autodesk Moldflow Insight software and validated with a experiment. According to obtained outcome the increase of melt flow speed results with significant (but linear) increase of injection pressure and for investigated part the switchover point has significant impact above 98%. The nonlinear behavior of clamping force during injection phase was observed because of the energy dissipation on polymer flow. The experiment validated the direction of changes whereas the differences in comparison to simulations were observed because of the limitations of measurement systems that were present in injection molding machine.